The present invention relates to an apparatus and method for measuring the strength of individual abrasive grains.
It is known to measure the strength of a batch of grains by placing a small sample of the batch in a capsule with a steel ball, agitating it vigorously for a fixed amount of time, and measuring the amount of fragments produced. One disadvantage of this method is that it measures the strength of the weakest grains while giving little information about the strength of the strongest grains. Another disadvantage is that it has a low ability to discriminate among batches of similar hardness.
It is also known to measure the strength of individual grains by crushing them one at a time in a press. In this method individual grains are placed in a press between two anvils which move together along a single axis with increasing force until the grain fractures. One disadvantage of this method is that it takes one to two minutes to measure the strength of each grain. This method is avoided in commercial applications because of this lack of speed.
For the foregoing reasons, there is a need for a speedy means of measuring the strength of individual abrasive grains.